This study was performed in order to investigate effects of CuO nanoparticle (50 nm) and CuSO4, 5H2O as a disinfectant, on growth indices and gill histopathology of grass carp fingerlings. For this aims, 200 grass carp fingerlings (4.5±0.5g), were divided to four treatments included: copper sulfate (1, 1.5 mg/L), CuO–NPs) 100, 200 mg/L) and control group with triplicate, then were studied during 30 days. They were fed with 0.8 French BioMar carp and sampled on, 5 th,10 th, 15th, 20th, 30 th day after exposure. Growth indices of fishes were analyzed by SPSS software. Also, the gill microscopic studies were done. Specific growth rate, condition index, average weight and survival respectively, in copper sulfate 1.5 mg/L group and then CuO-NPs 200 mg/L had significantly decreased (p<0.05). But other growth indices did not have significant differences. All treatments had gill injuries, specially in copper sulfate 1.5 mg/L several abnormalities such as hyperplasia, congestion, deformity in secondary lamella and degeneration in primary lamella, were observed. It seems that copper sulfate 1.5 mg/L, then CuO -NPs 200 mg/L, showed higher influence on growth indices, survival and pathological signs on gills. According to important role of gill in gas exchange, also synergy between these two substances, precise use of copper sulfate concentrations as disinfectant for any kind of fishes and necessity to consciously use of CuO-NPs is recommended. |